The Contractor shall, on a task order basis, conduct Phase I, II, or III clinical trials under the National Institute on Drug Abuse (NIDA), Division of Treatment Research and Development (DTR&D) program for [unreadable]Medications Development of Stimulant Dependence (MDS)'. These sites will evaluate the clinical utility of pharmacotherapeutic compounds for the treatment of drug abuse. Specifically, pharmacotherapeutic compounds to reduce the use of stimulants (i.e., cocaine and methamphetamine) and prevent relapse will be investigated. The results of these clinical trials may be submitted to the FDA in support of New Drug Application (NDA) submissions. The major emphasis of this contract will be on clinical trials to evaluate the clinical pharmacology, efficacy and safety profiles of the candidate compounds.